Fat burning zones “the myths”

This guest blog is a very interesting read. FLM Training would like to thank guest blogger Rob Barron for taking the time to write this. Rob is an experienced endurance athlete having completed several competitive Iron Men, Triathlons and Endurance Cycling events and has a wealth of knowledge in this area. Don’t forget to leave your comments below…

Dave Smith a former GB coach and national road coach has lots of accolades to his CV. From tour de France stage winners, Olympic medallists and his help has also assisted F1 drivers. His expertise and knowledge has helped dozens try to beat the fat.

We all agree that there is such a thing as the “fat burning zone”. There is certainly a level of intensity at which fat contributes a greater proportion of energy to fuel exercise. However the level of intensity varies from one individual to another and from day to day, based on training status and nutritional.

For example, if you wake up and exercise in a fasted state, you’ll burn more fat and at higher intensities than after a carbohydrate breakfast.

Okay firstly we know 1 gram of fat is worth 9 calories. Since the ‘fat-burning zone’ exercise burns roughly 140 to 180 calories in 30 minutes, with an estimate of 50 to 60 percent of those calories coming from fat it translates to only 8 to 12g of fat in 30 minutes.

The second reason to avoid long slow training sessions is that they increase appetite, whilst high intensity intervals suppress appetite. An interval session will have a greater calorie cost when recovery metabolism is included, and also suppresses hunger.

Graduates at the Laval University in Quebec * studied 2 groups that participated in different exercise sessions. 17 subjects trained on an indoor bike four to five times per week for 20 weeks, with workouts lasting from 30 to 45 minutes and exercise intensity ranged from 60-85 per cent of maximal heart rate.

The second group of 10 subjects completed 30-minute workouts at an intensity comparable to that attained by the first group. However, the second group also conducted 19 short and 16 long interval sessions during their 15-week programme. The short-interval sessions consisted of 10 to 15 intervals lasting for 15-30 seconds, while the long-interval efforts were composed of four to five intervals with durations of 60-90 seconds. The results showed the total energy expenditure during training was twice as great in the first group as in the second group – they burned more calories. However, each group achieved about a 30% increase in maximal aerobic capacity. Most surprisingly however, the interval-trained athletes (who performed less total work remember) had a 9x greater loss of body fat than the first group.

This research was done more than 20 years ago, yet the misconception still exists that low intensity exercise in your ‘fat burning zone’ is best for losing body fat, hence my palming of the face last week.

To become better at fat burning, ride in a fasted state and ride long. Don’t fuel up on cereals and gels before – that will turn your fat burning switch off. Do all of this and keep riding when you feel empty to force your muscle to make powerful adaptations

* ‘lmpact of Exercise Intensity on Body Fatness and Skeletal Muscle Metabolism, ‘ Metabolism, vol. 43(7), pp 814-818, 1994)

 

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